Vane-ring for turbines.



Patented Sept. 7, 1909.

B LJUNGSTRDM vm RING r01; TURBINES. APPLICATION FILED I43. 16, 1908.

BIRGER LJUNGSTRfiM, 0F STOCKHOLM, SWEDEN.

VANE-RIN'G' FOR TURBINES.

Specification of Letters Patent.

Patented Sept. '7, 1909.

Application filed March 16, 1908. Serial No. 421,381.

To all whom it may concern:

Be it known that I, BIRGER LJUNos'rRoM, of 18 Grefmagnigatan, Stockholm, Sweden, a subject of the King of Sweden, have invented certain new and useful Improvements in Vane-Rings for Turbines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to figures of reference marked thereon, which form'a part of this specification.

This invention relates to improvements in vane rings for fluid pressure turbines in which the rings are composed of a series of vanes secured to connecting strips so as to form a perforated cylinder, and the invention has for its object to provide reinforcing or stiffening rings for said strips, and consists in forming projections on the strips and rings adapted to be connected to one another by swaging the edges or by distorting a separate securing member to form a connection.

In the drawing accompanying and forming part of this specification I have shown in detail certain advantageous forms of embodiment of the invention, which,to enable those skilled in the art to practice the same,

will be set forth in detail in the following description, while the novelty of the illvention will be included in the claims succeeding said description.

Referring to said drawingsFigures 1' and 2 are sectional and side views respectively, of a portion of a vane ring for an axial turbine illustrating one form of connection between the connecting strips and reinforcing or stilfening' members. Fig. 3 is a cross section of a modified form of stiffening member and illustrating a roller as a means for clamping said stiffening memher to a connecting strip. Figs. 4, 6 and 7 are similar views, illustrating modified forms of connecting means, and Fig. 5 is a cross section of a radial turbine provided with further modified forms of connections between the connecting strip and stiffening member.

In the vane ring illustrated in Figs. 1 and 2 the numeral 1 designates the vanes, preferably crescent-shaped in cross section, and connected in series by means of strips 3 which have slots formed therein conformmg to the cross section of the vanes. The ends of the vanes project into the slots of the strips and are secured to said strips by welding, which may be carried out by means of a flame from 1 a bellows pipe or from an acetylene or hydrogen burner, or by means of an electric voltaic are brought into contact with the projecting ends and causing that portion of the vanes to smelt.

The strips .3 are preferably in the form of rings or segments, or they may first have the form of straight strips in which the slots are made, and when the vane ends are fastened in the manner described said strips are bent into the form ofa ring. The connecting members or strips 3 are then secured to thicker stiffening or reinforcing bands or rings 4:, and any portion of the strip 3 which projects beyond the edges of the vanes 1 and all projecting edges or unevenness may be worked down in any manner, as by bending or grinding, until the strips 8 conform to the width of the vanes.

The stiffening rings may be provided with concentric projecting edges, which are, by the aid of suitable tools, such as roll 10 shown in Fig. 8, made to change their form after the ring has been placed in proper position and caused to engage and lock with undercut, concentric edges on the connecting strip.

As shown at the upper portion of Fig. 1, the connection between the stiffening or reinforcing ring and connecting strip is effected by providing a flange, as 8, on one edge (shown on an enlarged scale in Fig. 3) of the stifiening ring 1 which fits into a corresponding. recess formed in the strip 3. The other edge of said ring has a lateral projection 9, which is swaged or pressed down, preferably by means of a roll 10 into the position indicated by dotted lines (Fig. 3,) against a corresponding surface on strip 3 and holds the latter locked against the shoulder 8.

At the lower portion of Fig. 1 the ring 4: is shown as provided with a longitudinal groove 11 to receive the strip 3, whose periphery conforms to the shape of the groove in the ring, and is locked therein by means of the projection 9 on the latter being swaged or pressed into the position shown. The central stiffening ring shown in Fig. 1 is connected to the strips 3 by means of a separate securing member or ring 7 inserted between the central ringandthe strips. .Such securing members may be of drawn wire, soft steel, brass, copper, nickel or any suitable material of suitable profile, and the arrangement is advantageous in that the joints may be made where it is necessary to change the form of the member or ring i As shown in Fig. 4, one side of the member 7 is drawn to correspond to the shape of the joint between the strip 3 and ring t, while the other side of said member 7 is swaged into a shape corresponding to that of the joint, as indicated in dotted lines.

In Fig. 5 the stiffening rings 4 are shown as connected to the strips 3 by means of dovetailed grooves formed in the rings 4 embracing corresponding ribs on the strips 3. On one side of the central stiffening ring between it and the strip there is inserted a securing ring 7 which has a dovetailed grooveon each side embracing corresponding ribs on the ring and strip. Such eon nections are effected either in the manner indicated in Fig. 6, wherein the interior walls of the groove are normally parallel and after the insertionof the rib of the strip said walls are pressed or swaged into contact with the sides of the rib, or said connection may be efiected as illustrated in Fig. 7 wherein the securing ring 7 has a flange on each edge,

which is swaged down to conform to the configuration of the ribs on the sides of the strip and ring.

The provision of separate securing rings is advantageous in that a joint may be more easily effected, where a considerable change is made in the form of the concentric edges or' projections, than is possible where said ring is made integral with the stifiening ring, because in order to get the necessary resistance against the centrifugal strains they must be made of a comparatively hard material.

Experiments which have been made show that in cylindrical vane rings the joints in question may easily be made with the edges and projections in one piece with the stiffening rings, even if they are made of spring steel with 0.60 per cent. to 0.70 per cent. of carbon. If nickel steel be used a still larger per cent. of carbon may be added, and in both cases stiffening rings of suflicient strength may be obtained.

It is evident that the separately arranged concentric edges or projections need not be folded on the stilfening rings before they are secured in place, but the adjacent ribs may be so arranged that the parts are, by means of the folding, joined simultaneously.

I claim 1. A unitary vane structure, comprising a series of vanes, strips connected to the ends of said ,vanes and reinforcing rings in swaged connection with said strips.

2. A unitary vane structure, comprising a plurality of vanes, a strip to which said vanes are connected, a reinforcing member for said strip and means associated therewith distorted to secure the reinforcing member and strip together.

8. A unitary vane structure, comprising a series of vanes, strips fixed to the ends of said vanes having projections thereon, and reinforcing rings having projections adapted to be locked to the aforesaid projections.

In testimony, that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

BIRGER LJUNGSTROM.

Witnesses K. E. VVIBERG,

A. H. Coon. 

